A shopkeeper sells an article at a loss of $$12\frac{1}{2}$$% . Had he sold it for Rs. 51.80 more, he would have earned a profit of 6% . The cost price of the article is = ?

Let C.P. be Rs. x Then
(106% of x) - $$\left( {87\frac{1}{2}\% \,\,{\text{of}}\,x} \right) = 51.80$$
$$\eqalign{ & \Rightarrow 18\frac{1}{2}\% \,\,{\text{of}}x = 51.80 \cr & \Rightarrow x = \left( {\frac{{51.80 \times 100 \times 2}}{{37}}} \right) \cr & \therefore x = 280 \cr} $$